1. Field of the Invention
The present invention relates to a piezoelectric ceramic, to a piezoelectric element comprising it, and to a piezoelectric device comprising the piezoelectric element.
2. Related Background Art
Ultrasonic motors and piezoelectric transducers are examples of applications of piezoelectric ceramics in high-power devices. Such devices require materials that operate at high oscillation speeds and exhibit large amplitudes.
Examples of piezoelectric ceramics that can be driven at high oscillation speeds include piezoelectric ceramics comprising a main component which is a system of lead zirconate titanate (Pb(Zr, Ti)3, (PZT)), as a perovskite-type compound, and an accessory component, known as a relaxer. It is known that particularly high oscillation speeds can be obtained with lead zirconate titanate/lead zinc niobate (Pb(Zr, Ti)O3—Pb(Zn, Nb)O3 (PZT-PZN))-based piezoelectric ceramics, such as described in Japanese Patent Publication No. 2957564 and Japanese Patent Publication No. 2957537.